1. Field of the Invention
This invention relates to a halogen-free resin composition, a covered wire covered with the halogen-free resin composition and a wiring harness with a plurality of the covered wires.
2. Description of the Related Art
An electric covered wire, in which a conductive wire, such as a copper wire, is covered with a resin composition based on a polyvinyl chloride resin, is usually used for wiring as a covered wire in a vehicle. A polyvinyl chloride resin has good material characteristics, such as high flame retardant performance because of a self-extinguish material, and good adjustability of hardness by adding a plasticizer and high wear-resistance. However, the polyvinyl chloride resin generates harmful gases such as halogen gas when burning by incineration or vehicle fire, and it makes environmental problems.
To overcome this problem, in recent years, a halogen-free resin composition based on a polyolefin resin has been developed (for example, refer Patent document 1: Japan Patent Application Published No. 2005-248110). In the Patent document 1, the halogen-free resin composition including an amorphous olefin copolymer, an aromatic vinyl conjugated diene block copolymer with a hydrogen additive, and a polyolefin resin is described as the halogen-free resin composition improving weather resistance, formability, heat-resistance, abrasive resistance and deformation recoverability. Also, in the patent document 1, an inorganic flame retardant, such as a magnesium hydroxide as a flame retardant can be added to the halogen-free resin composition.